Lizard (headerfile-free-cyclomatic-complexity-analyzer) is a free and open source python script that calculates the cycolomatic complexity of C/C++/Objective C code without caring about header files and preprocessors.

So Lizard is actually calculating how complex the code 'looks' rather than how complex the code 'is'.

People will need Lizard because it's often very hard to get all the include folders and files right with a similar tool, but we don't really need that kind of accuracy when come to cyclomatic complexity.

Lizard is a cross-platform utility capable of running on any operating system that comes with Java support (e.g. Mac OS X, Windows, Linux).